multi-agent-mux/.agents/reports/reviewer-agy-01/report-c2b1b804.md

PR Review Report: Loop Marker Isolation (Prevent Tests Taking Checkout Loop Lock)

• Reviewer Agent: agy (session: herdr:reviewer-agy-01)
• Job ID: c2b1b804
• Role: Reviewer
• Target Branch: test/loop-marker-tmp
• Verification Directory: /var/folders/q_/68sxgw3j073dgjg8wl9s08vw0000gn/T/mam-review/loop-20261008T234013Z-4f5d21/1
• Base Commit: 97c2946ee0e11eabcecafe6407755c33c0289218 (main)
• Head Commit: a93c9bf29279f65ce0b9c9fb2c1aeea90a659420
• Tree SHA: 741c19ba4c17601768b06684d5843d218a72beb1
• Cumulative Commits:
  • a93c9bf: test(loop-lock): the b13 runs of the checkout's run_loop.sh take a loop lock of their own

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1. Executive Summary

When running tests from the repository root, tests/test_o3_scoped_guard.py's test_b13_reexec_preserves_original_argv and test_b13_no_freeze_switch_disables_reexec previously invoked the checkout's real run_loop.sh with cwd=REPO_ROOT without specifying MAM_LOOP_MARKER. Because run_loop.sh derives MAM_REAL_ROOT=REPO_ROOT and defaults MAM_LOOP_MARKER="${MAM_LOOP_MARKER:-$MAM_REAL_ROOT/.mam/loop-guard-active}", mam_acquire_loop_lock executed mkdir -p "$(dirname "$MAM_LOOP_MARKER")", creating .mam/ in the real checkout and briefly acquiring the live loop guard.

Commit a93c9bf surgically resolves this issue:

1. tests/test_o3_scoped_guard.py: Sets MAM_LOOP_MARKER=str(tmp_path / "loop-guard-active") for both b13 tests.
2. A comprehensive audit across all test files confirms no other test invokes the checkout's run_loop.sh past argument parsing without an isolated marker or sandbox.
3. Added tests/test_loop_marker_isolation.py:test_l1_no_test_takes_the_loop_lock_of_its_checkout which copies the checkout, runs all tests reaching the lock, and asserts no .mam/ is created in the copy.
4. Added an explicit assert not (copy / ".mam").exists() check to tests/test_issue17_workspace_root_isolation.py:test_w1.
5. Executed all target and related suites under both (a) unset WORKSPACE_ROOT and (b) WORKSPACE_ROOT=<sentinel>: 57 passed, 0 failed, with the sentinel directory remaining 100% empty and no .mam/ left behind in the worktree.
6. Product code (.agents/skills) remains 100% untouched.

All review criteria and task requirements are satisfied. The final verdict is PASS.

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2. Evaluation of Task Requirements

Requirement	Description	Status	Details
1. Comprehensive Audit of run_loop.sh Tests	Investigate all candidate tests invoking run_loop.sh. Verify whether they execute the checkout's script past argument parsing without custom marker/sandbox.	PASS	Complete audit conducted across all 16 candidate test modules (detailed in Section 3). Only the two b13 tests in test_o3_scoped_guard.py were unprotected.
2. Temporary Marker Isolation	Point MAM_LOOP_MARKER under tmp_path for affected tests while preserving deliberate lock tests and avoiding harmful global/autouse fixtures.	PASS	Directly specified MAM_LOOP_MARKER=str(tmp_path / "loop-guard-active") in test_b13_reexec_preserves_original_argv and test_b13_no_freeze_switch_disables_reexec. Deliberate lock test suites (test_o2_race_free_lock.py, etc.) retain their intended marker semantics without interference.
3. Regression Tests	Add a regression test running candidate tests in a clean copy of the checkout and asserting no .mam/ is created. Verify failure prior to fix.	PASS	Added tests/test_loop_marker_isolation.py (test_l1), and added .mam absence assertion in tests/test_issue17_workspace_root_isolation.py:test_w1. At base commit 97c2946, test_b13 created $REPO_ROOT/.mam on lock acquisition, causing test_l1 to fail.
4. Suite & Sentinel Verification	Run modified test files + test_o2_race_free_lock.py, test_o3_scoped_guard.py, test_issue17_workspace_root_isolation.py under (a) unset WORKSPACE_ROOT and (b) WORKSPACE_ROOT=<sentinel>, verifying sentinel is empty and no .mam/ exists in tree.	PASS	Both runs (a) and (b) passed completely (57/57 passed each). Sentinel directory remained 100% empty (find "$SENTINEL" -type f returned 0 files), and verification tree has no .mam/ directory.

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3. Comprehensive Audit Table of run_loop.sh Candidate Modules

Test File	Reference / Invocation	Reaches Loop Lock?	Exclusion / Remediation Rationale
tests/test_b7_diff_untracked.py	Lines 174, 189: read_text(), bash -n	No	Static code inspection and bash syntax check only; does not execute run_loop.sh.
tests/test_deploy_freshness.py	Line 473: read_text()	No	Static text inspection of MAM_ENV_FILE export; does not execute script.
tests/test_issue17_workspace_root_isolation.py	Runs tests in tmp_path / "checkout" copy	Yes (in copy)	Runs isolated nodes in a temporary checkout copy; protected by test-level markers in the sub-tests.
tests/test_issue21_acceptance.py	Line 298: subprocess call	Yes	Already sets env["MAM_LOOP_MARKER"] = str(marker) where marker is in tmp_path.
tests/test_issue21_loop_b.py	N/A	No	File does not exist / references removed in prior refactors.
tests/test_issue21_worktree_prereqs.py	Line 405: test_t2_8	Yes	Already sets "MAM_LOOP_MARKER": str(marker) where marker is in mam_sandbox.
tests/test_issue25_plan_reuse.py	Line 355: --help; Line 367: test_p7b	Yes	--help exits before lock; test_p7b already sets "MAM_LOOP_MARKER": str(marker) in tmp_path.
tests/test_issue36_prompt_transport.py	Line 540: _run_shell_loop; Line 630: read_text()	Yes	Runs inside temporary fixture workspace ctl with explicit "MAM_LOOP_MARKER": ctl / ".mam" / "loop-marker".
tests/test_issue5_phase0_contracts.py	Line 481: read_text()	No	Static assertion in baseline text check.
tests/test_issue5_phase3_loop.py	Line 151: --help; Lines 165, 183	Yes	--help exits before lock; execution tests already pass env["MAM_LOOP_MARKER"] = str(tmp_path / "loop-marker").
tests/test_issue5_phase4_runtime.py	Lines 142, 166: --help	No	Only executes --help to test freeze directory bypass logic; exits before lock acquisition.
tests/test_loop_cli.py	Line 51: test_creator_parses...; others: --help / bad args	Yes	Argument errors and --help exit before lock; test_creator_parses... already sets "MAM_LOOP_MARKER": str(tmp_path / "loop-guard").
tests/test_o1_rebuttal.py	Line 24: function extraction; Line 166: read_text()	No	Extracts helper functions to execute standalone or reads text; never runs run_loop.sh main entry point.
tests/test_o2_race_free_lock.py	Line 203: test_o2_12	Yes	Already sets run_env["MAM_LOOP_MARKER"] = str(tmp_path / "loop-guard-active").
tests/test_o3_scoped_guard.py	Lines 387, 471: test_b13_*	Yes (Defect)	Remediated: Added MAM_LOOP_MARKER=str(tmp_path / "loop-guard-active") to both invocations.
tests/test_tier4_e2e.py	Line 285: mam_sandbox copy	Yes	Runs inside isolated mam_sandbox directory tree, not the repository checkout.

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4. Test Suite Execution & Verification Results

All tests were executed within the verification tree: /var/folders/q_/68sxgw3j073dgjg8wl9s08vw0000gn/T/mam-review/loop-20261008T234013Z-4f5d21/1

4.1. Run (a): Without WORKSPACE_ROOT (Requirement 4)

AGENT_PYTHON_BIN=/Users/godopu16/PuKi/laa/canary_projects/multi-agent-mux/.venv/bin/python \
PYTHONDONTWRITEBYTECODE=1 \
env -u WORKSPACE_ROOT \
/Users/godopu16/PuKi/laa/canary_projects/multi-agent-mux/.venv/bin/python \
  -m pytest -p no:cacheprovider -q --basetemp=/tmp/pytest-loop-marker-a \
  tests/test_loop_marker_isolation.py \
  tests/test_o3_scoped_guard.py \
  tests/test_o2_race_free_lock.py \
  tests/test_issue17_workspace_root_isolation.py

• Exit Code: 0
• Output: 57 passed in 46.27s
• Tree Check: .mam does not exist in the verification directory.

4.2. Run (b): With WORKSPACE_ROOT= (Requirement 4)

SENTINEL=/tmp/sentinel-review-b
mkdir -p "$SENTINEL"
AGENT_PYTHON_BIN=/Users/godopu16/PuKi/laa/canary_projects/multi-agent-mux/.venv/bin/python \
WORKSPACE_ROOT="$SENTINEL" \
PYTHONDONTWRITEBYTECODE=1 \
/Users/godopu16/PuKi/laa/canary_projects/multi-agent-mux/.venv/bin/python \
  -m pytest -p no:cacheprovider -q --basetemp=/tmp/pytest-loop-marker-b \
  tests/test_loop_marker_isolation.py \
  tests/test_o3_scoped_guard.py \
  tests/test_o2_race_free_lock.py \
  tests/test_issue17_workspace_root_isolation.py

• Exit Code: 0
• Output: 57 passed in 48.74s
• Sentinel Contents: find "$SENTINEL" -type f returned 0 files (100% clean).
• Tree Check: .mam does not exist in the verification directory.

4.3. Auxiliary Related Loop Suites

Executed test_issue5_phase3_loop.py, test_issue5_phase4_runtime.py, test_loop_cli.py, test_issue25_plan_reuse.py, test_o1_rebuttal.py:

• Exit Code: 0
• Output: 53 passed in 44.25s

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5. Non-Functional & Safety Checks

1. Surgical Precision:
   • git diff --stat 97c2946..a93c9bf shows 3 files changed (+55 lines), strictly confined to tests/.
   • Zero changes to .agents/skills.
2. Portability:
   • Compatible with macOS, Python 3.9+, and bash 3.2.
   • Preserves POSIX shell semantics and subshell environment isolation.
3. Safety & Cleanliness:
   • No interaction with real .mam.env, live daemon, or active sessions.
   • Clean git status; follows test(loop-lock): ... commit naming convention.

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6. Conclusion & Final Verdict

The changes resolve the checkout loop lock acquisition defect surgically and completely. Tests executing run_loop.sh are thoroughly isolated, regression tests verify zero .mam creation, and all suites pass with zero regressions.

[VERDICT: PASS]